Inclination detecting optical sensor and a process for producing the same

ABSTRACT

It is an object of the present invention to provide an optical sensor that has a simple structure and which yet enables positive detection of the inclination of an object of interest, and also to provide a process for producing the same. The improved sensor comprises a light-emitting element, a light-receiving element, a body having an inclined surface formed between the two elements, a lid fitted over the body, and a sphere placed between the body and the lid in such a way that it is capable of movement down the inclined surface. In the process, a light-emitting device and a light-receiving device, both subjected to primary molding, are respectively set between the lower and the middle part of a split mold and between the middle and the upper part of the mold; secondary molding is then performed by injecting an opaque resin into the cavity defined by the lower, middle and upper parts of the mold.

TECHNICAL FIELD

The present invention relates to an optical sensor for detecting theinclination of an object.

BACKGROUND ART

A widely known type of optical sensor is a photointerrupter thatcomprises a light-emitting device and a light-receiving device forreceiving the light from said light-emitting device and which checks forthe presence of a light-shielding object between the two devices bydetermining whether the light generated from the light-emitting deviceis interrupted by the object.

A conventional type of inclination detecting sensor that adopts aphotointerrupter is shown schematically in FIG. 11 and comprises thefollowing components: photointerrupter 71 consisting of a light-emittingdevice 71a and a light-receiving device 71b that is provided in aface-to-face relationship with the device 71b in such a way as to becapable of receiving the light issuing from it; a resin-molded lowercase 72 with the top 72a being open to accommodate the photointerrupter71; an upper case 73 fitted on the top 72a of the lower case 72; and alight-shielding sector 74 adapted to swing between the light-emittingand receiving devices 71a and 71b about a shaft 73b that is supported ona shaft bearing 73a directed downward from the upper case 73 to extendinto the lower case 72.

In this type of optical sensor, the light shield 74 supported on thebearing 73a of the shaft 73b is subject to the gravitational effect andnormally positioned below the shaft 73b. For its operation, the sensoris either carried or fixed on an object which to be is checked for theoccurrence of inclination greater than a certain angle. If the objectand, hence, the sensor is either in a level position or inclined at anangle not exceeding a specified value, the light issuing from thelight-emitting device 71a toward the light-receiving device 71b has itsoptical path blocked by the light shield 74 and is not picked up by thelight-receiving device 71b. On the other hand, if the object is inclinedin either direction to exceed the specified angle, the light shield 74is accordingly displaced in position relative to the photointerrupter 71fixed to the lower case 72 and the light issuing from the device 71atravels uninterrupted by the shield 74 and it is picked up by thelight-receiving device 71b, whereupon an electric current flows betweenthe associated lead terminals to enable the detection of the inclinationof the object.

With the recent advances in the technologies of semiconductors andoptical devices, the demand for optical sensors of the above-describedtype that employ a photointerrupter has increased, requiring not only afurther reduction in the number of parts to be assembled but also theadoption of a simplified fabrication process.

In fact, however, the conventional optical sensors requires that theupper case 73 be equipped with the bearing 73a for enabling theprovision of the light shield 74. What is more, the light shield 74which has a specific form adapted for the detection of inclination musteither be provided integrally with the shaft 73b or made as a separatemember and thereafter connected to the latter in the assembling step.This increases the complexity of mechanical design, making it difficultto reduce the number of parts below a certain level. It is alsodifficult to simplify the fabrication process beyond a certain level.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide an optical sensorthat is simple in design and which yet enables positive detection of theinclination of an object of interest, and also to provide a process forproducing the same.

This object of the invention can be attained by an inclination detectingoptical sensor comprising:

a light-emitting element;

a light-receiving element for receiving the light from thelight-emitting section;

a body having an inclined surface formed between the light-emitting andlight-receiving elements;

a lid fitted on the body; and

a sphere placed between the body and the lid in such a way that it iscapable of movement down the inclined surface.

In a preferred embodiment, the light-emitting and receiving elements areprovided in the central part of the body along the inclined surface onopposite sides thereof.

In another preferred embodiment, the light-emitting and receivingelements are provided near the end portions of the body along theinclined surface on opposite sides thereof.

This object of the invention can also be attained by a process forproducing an inclination detecting sensor comprising the steps of:

providing a light-emitting and a light-receiving device that are eachformed by applying primary molding of a transparent resin to asemiconductor chip mounted to establish electrical connection to leadsat an end thereof;

applying secondary molding of an opaque resin to said light-emitting andreceiving devices so as to form a body having a hollow space defined byan inclined surface between said two devices;

placing a sphere into said hollow space, and

fitting a lid on said body in such a way as to close said hollow space.

In a preferred embodiment, secondary molding is performed by filling acavity with the opaque resin, the cavity being defined by an upper, amiddle and a lower part of a split mold, with either one of thelight-emitting and receiving devices being positioned between the lowerand middle parts whereas the other is positioned between the upper andmiddle parts.

In a more preferred embodiment, secondary molding is performed with asplit mold having two middle parts, one of which has a molding surfacewith a projecting part that provides a recess in the body while theother has a molding surface that provides outer surfaces for the body.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an inclination detecting opticalsensor according to the first embodiment of the invention, with the liddetached from the body;

FIG. 2 is a perspective view of the light-emitting element for use inthe optical sensor shown in FIG. 1;

FIG. 3 is a cross section of the sensor shown in FIG. 1;

FIG. 4 is a longitudinal section of an inclination detecting opticalsensor according to the second embodiment of the invention;

FIG. 5 is a perspective view showing the principal part of aninclination detecting sensor according to the third embodiment of theinvention, with the lid detached from the body;

FIG. 6 is a perspective view of the light-emitting device in the sensorshown in FIG. 5;

FIG. 7 is a cross section of the sensor shown in FIG. 5;

FIGS. 8(a), 8(b), 8(c) and 8(d) shows a fabrication sequence for thesensor of FIG. 5;

FIG. 9 illustrates how a sphere is loaded into the sensor of theinvention with the lid being then fitted on the body;

FIG. 10 is a perspective view showing the principal part of aninclination detecting sensor according to the modification of the thirdembodiment; and

FIG. 11 is a sectional view of the structure of a prior art inclinationsensor.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the inclination detecting optical sensor according to thepresent invention will now be described in detail with reference toaccompanying drawings.

FIG. 1 shows schematically the construction of an optical sensoraccording to the first embodiment of the invention. As shown, the sensorcomprises a light-emitting element 1 that emits light in response to asupplied electric signal, a light-receiving element 2 provided in aface-to-face relationship with the light-emitting element 1 such as toreceive the light from the element 1, a body 3 that fixes both thelight-emitting element 1 and the light-receiving element 2 by sealingwith an opaque resin and which is so formed as to provide an inclinedsurface 3a between the two elements, a lid 4 fitted over the body 3, anda sphere 5 which is accommodated between the body 3 and the lid 4 insuch a way that it is capable of movement down the inclined surface 3a.

As shown specifically in FIG. 2, the light-emitting element 1 comprisesa pair of lead electrodes 6a and 6b which are each made of a conductorsuch as Fe, a light-emitting diode 7 bonded to a tab at the distal endof lead electrode 6a by means of Ag paste, and a Au wire 8 establishingelectrical connection between the light-emitting diode 7 and the otherlead electrode 6b. The diode 7 and the Au wire 8 are sealed with atransparent resin together with the distal ends of lead electrodes 6aand 6b to form a sealed package 9. The package 9 has a rectangular strip9a formed near the diode 7 to protrude in forward direction so as toprovide a window (to be described later) in the body 3 which is made ofan opaque resin.

The light-receiving element 2 is constructed in the same way as thelight-emitting element 1, except that the light-emitting diode isreplaced by a phototransistor which will generate a voltage between theassociated lead electrodes upon illumination with light. Therefore, thelight-receiving element 2 is not described here in detail.

As shown by cross section in FIG. 3, the body 3 which is made of anopaque resin has a window 3b formed on the light-emitting element sidein registry with the projection 9a on the sealed package 9 in such a waythat the light issuing from the light-emitting diode 7 can pass throughthe projection 9a toward the light-receiving element 2. The body 3 alsohas a window 3c formed on the light-receiving element side in registrywith the projection on a sealed package 13 in such a way that the lightfrom the light-emitting diode 7 can be received by the phototransistor10.

The body 3 has two inclined surfaces 3a which form a specified angle Θwith respect to a reference plane (or a level plane) on which theoptical sensor is to be carried. In FIG. 1, the inclined surfaces 3a areprovided symmetric with each other but this is not the sole case of theinvention and a single inclined surface or two asymmetric inclinedsurfaces may be provided depending upon the specific object of use ofthe sensor or its design specifications. Needless to say, the inclinedsurfaces may partly or entirely be curved.

The first embodiment refers to the case where the light-emitting element1 and the light-receiving element 2 which constitute a photointerrupterare sealed in an opaque resin together with the body 3 in which theinclined surfaces 3a are formed. Alternatively, that part of the body 3in which the inclined surfaces are to be formed may be preparedseparately from the other parts and thereafter combined with the latter.

Thus, the optical sensor according to the first embodiment of theinvention comprises the light-emitting element 1, the light-receivingelement 2 for receiving the light from the element 1, the body 3 havingthe inclined surfaces 3a provided between the two elements, the lid 4fitted over the body 3, and the sphere 5 (typically made of steel) whichis accommodated between the body 3 and the lid 4 in such a way that itis capable of movement down the inclined surfaces 3a. In addition, thelight-emitting element 1 and the light-receiving element 2 are providedon opposite sides of the central area where the two inclined surfaces 3ameet. Because of this arrangement, the sphere 5 rests at the jointbetween the two inclined surfaces 3a if the inclination of the objectcarrying the sensor does not exceed angle Θ. As a result, the lightissuing from the light-emitting element 1 is interrupted by the sphere 5and does not reach the light-receiving element 2.

If, on the other hand, the object is inclined in either direction(clockwise or counterclockwise) to exceed angle Θ, the sphere will movein the direction of inclination and, hence, the light issuing from thelight-emitting element 1 travels uninterrupted by the sphere 5 to reachthe light-receiving element 2, where it is picked up as a detectionelectric signal.

In this way, the optical sensor according to the first embodiment of theinvention insures that the inclination of the object carrying the sensorcan be easily detected by means of an electric signal that is generatedif the light-receiving element 2 picks up the light issuing from thelight-emitting element 1.

An optical sensor according to the second embodiment of the inventionwill now be described with reference to FIG. 4. As shown, the sensor isconstructed in the same way as in the first embodiment except that twopairs of light-emitting and receiving elements, one consisting of alight-emitting element 11a and a light-receiving element 12a and theother consisting of 11b and 12b, are provided in the two end portions ofthe body 3.

Thus, the optical sensor according to the second embodiment of theinvention has the pair of light-emitting element 11a and light-receivingelement 12a in one end portion of the body 3 and the pair oflight-emitting element 11b and light-receiving element 12b in the otherend portion. If the object on which the sensor is carried is inclined ata small angle that does not exceed the angle Θ the inclined surfaces 3aform with the reference or level plane, the sphere 5 rests in thecentral position of the body which is indicated by a solid line in FIG.4. As a result, the light-issuing from the light-emitting elements 11aand 11b is picked up by the corresponding light-receiving elements 12aand 12b, whereupon an electric current is generated from thelight-receiving elements.

If the object carrying the sensor is inclined in either direction, saycounterclockwise, to exceed the angle Θ, the sphere 5 moves to the leftin FIG. 4 and prevents the light-receiving element 12a from picking upthe light issuing from the light-emitting element 11a and no electriccurrent will be generated from the element 12a. If the object isinclined clockwise to exceed the angle Θ, the sphere 5 will move to theright and prevents the other light-receiving element 12b from picking upthe light issuing from the light-emitting element 11b and no currentwill be generated from the element 12b.

Thus, according to the second embodiment of the invention, one candetermine the direction in which the object of interest has beeninclined to exceed a specified angle by checking which of the twolight-receiving elements 12a and 12b generates an electric current.

A third embodiment of the invention as it relates to an inclinationdetecting sensor are described below in detail with reference to FIGS.5-9.

To begin with, the structure of an inclination detecting sensorfabricated by the invention process will now be described.

As shown in FIG. 5, the sensor comprises a body 51 made of an opaqueresin, a hollow space 53 formed within the body 51 and defined by twoopposed inclined surfaces 52 that are formed in the upper part of thebody 51, a sphere 54 placed into the hollow space 53 in such a way thatit is capable of movement down either of the inclined surfaces 52, a lid55 secured to the body 51 in such a way as to close the hollow space 53containing the sphere 54, and a light-emitting device 56 and alight-receiving device 57 that are positioned within the body 51 inplanes that hold the inclined surfaces 52 therebetween and that aresymmetric with the sphere 54 positioned between said surfaces. In FIG.5, the light-emitting and receiving devices are hatched for the sake ofclarity. For protection against corrosion, the sphere 54 is preferablymade of stainless steel but this is not the sole case of the invention.The lid 55 is first formed as a separate member from the body 51 and itcan then be fitted into the top surface of the body 51. As will bementioned later in this specification, the lid 55 may be formed of anopaque resin as an integral part of the body 51. In this case, the lid55 is bent down to be fitted into the top surface of the body 51.

As shown specifically in FIG. 6, the light-emitting device 56 comprisesa pair of lead electrodes 58a and 58b which are each made of a conductorsuch as Fe, a light-emitting diode 59 bonded to a tab at the distal endof lead electrode 58a by means of Ag paste, and a Au wire 60establishing electrical connection between the light-emitting diode 59and the other lead electrode 58b. The diode 59 and the Au wire 60 areprimary molded in a transparent resin together with the distal ends oflead electrodes 58a and 58b to form a sealed package 61. The package 61has a rectangular strip 61a formed near the diode 59 to protrude inforward direction. As best shown in FIG. 7 which is a cross section ofthe sensor, the package 61 is given secondary molding in an opaque resinto form the body 51 such that a light-passing window is formed in theinner surface of the body to be contiguous to the projection 61a, thusallowing the diode 59 to emit light toward the hollow space 53 in thebody 51 via the window.

The light-receiving device 57 is constructed in the same way as thelight-emitting device 56, except that the light-emitting diode isreplaced by a phototransistor 68 which will cause an electric current toflow between the associated lead electrodes upon illumination withlight. Therefore, the light-receiving device 57 is not described here indetail.

The process for producing the sensor will now be described withreference to FIGS. 7 and 8.

First, a light-emitting and a light-receiving device are provided in aprimary molded form. Then, these devices are subjected to secondarymolding in an opaque resin according to the following procedure.

A split mold consisting of an upper, a middle and a lower part isprovided. The split mold is for forming a body in which both devices areto be sealed and fixed. As shown in FIG. 8(a), the primary moldedlight-emitting device 56 is set on the lower part of the mold, with theprojection 61a facing up. The lower part 63 has a molding surface 63athat defines the outer surfaces of the body including one lateralsurface and which is continuous to a ridge 63b. The vertical position ofthe package 61 of the device 56 is determined by the ridge 63b whichsupports its back side.

With the light-emitting device 56 set on the lower part 63, two sections64a and 64b of the middle part are set in registry with the lower part63 such that the device 56 is held between each section of the middlepart and the lower part as shown in FIG. 8(b). Stated more specifically,the first section 64a is set in such a way that the distal ends of leadelectrodes 58a and 58b to the device 56 are held between the firstsection 64a and the lower part 63 and that the outer surfaces of thebody including the bottom surface will be defined. The second section64b is set in a face-to-face relationship with the first section 64asuch that the projecting part formed at the distal end contacts theprojection 61a of the transparent resin package of the device 56 andthat the body is provided with a hollow space defined by opposedinclined surfaces.

With the first and second sections 64a and 64b of the middle part beingthus set in position, the light-receiving device 57 is set on the otherside of the middle part in such a position that it is symmetric with thelight-emitting device 56 as shown in FIG. 8(c). Stated morespecifically, the light-receiving device 57 is set in such a way thatthe distal ends of the associated lead electrodes will lie on the firstsection 64a whereas the projection of the transparent resin package ofthe device 57 contacts the projecting part of the second section 64b.

With the light-receiving device 57 being thus set on the sections 64aand 64b of the middle part of the split mold, the upper part 65 of themold which is formed symmetrically with the lower part 63 is set on thesections 64a and 64b of the middle part in such a way that thelight-receiving device 57 is held between the upper part 65 and each ofthe sections 64a and 64b as shown in FIG. 8(d). Like the lower part 63,the upper part 65 has a molding surface 65a that defines the outersurfaces of the body including the other lateral surface and which iscontinuous to a ridge 65b. The vertical position of the sealed packageof the light-receiving device 57 is determined by the ridge 65b whichsupports its back side.

The lower part 63, the sections 64a and 64b of the middle part and theupper part 65 which have been set in the manner just described abovedefine a cavity for the secondary molding to be performed with an opaqueresin. The cavity is filled with an opaque resin that is injectedthrough a runner (not shown) typically formed between the lower part 63and the middle part 64a or 64b. The injected resin is hardened to form abody in which both the light-emitting and receiving devices are securelysealed and which has a hollow space formed therein. The opaque resin tobe used in the secondary molding may be a polycarbonate or ABS resin.

After the opaque resin hardens, the respective parts of the split moldare removed to leave behind the body having the light-emitting andreceiving devices 56 and 57 fixed therein.

The thus formed body 1 has the hollow space 53. As shown in FIG. 9, asphere 54 is slid down a chute 67 to drop into the space 53. Thereafter,the lid 55 is fitted on the body 1 to close the hollow space 53, thusproviding an inclination detecting sensor according to the invention.For mass production of sensors, a number of spheres are accommodated ina parts feeder connected to a chute equipped with a shutter and thespheres are successively slid down the chute to drop into the respectivehollow spaces in an array of bodies.

The embodiment shown in FIG. 9 differs from the case of FIG. 5 in thatthe lid 55 is formed as an integral part of the body 51 and connectedthereto via a joint 55a such that it can be fitted onto the body 51. Theorder to fit it onto the body 51, the lid 55 may be bent down by meansof a metallic cylindrical roller that is pressed against the lid fromleft to right in FIG. 9.

In the embodiment described above, the light-emitting device is set onthe lower part of the split mold whereas the light-receiving device isset on the middle part. Needless to say, this is not the sole case ofthe invention and the secondary molding may be performed with thelight-receiving device being set on the lower part of the mold and thelight-emitting device on the middle part.

The inclination detecting sensor thus constructed operates in thefollowing manner. Suppose the case where the sensor is carried or fixedon an object which is to be checked for the occurrence of inclinationgreater than a certain angle.

If the object and, hence, the sensor is inclined at an angle notexceeding a specified value, say, Θ (see FIG. 5) with respect to a levelor reference plane, the sphere 54 rests in the reference positionbetween two inclined surfaces 52 and the light issuing from thelight-emitting device 56 is blocked by the sphere 54 and will not reachthe light-receiving device 57.

If the sensor is inclined in either direction to exceed angle Θ, thesphere 54 will move down one of the inclined surfaces 52 such that it isno longer situated between the light-emitting device 56 and thelight-receiving device 57. As a result, the light from the device 56 istransmitted direct to the light-receiving device 57 and an electriccurrent corresponding to the amount of light reception is generated fromthe phototransistor in the device 57.

If the quantity of the current generated from the light-receiving device57 is detected by electrical means, one can easily determine whether theobject of interest has been inclined to exceed angle Θ.

In the embodiment described above, the body of the sensor has twoopposed inclined surfaces but this is not the sole case of the inventionand a single inclined surface may of course be provided to enable thedetection of an inclination in a specified direction.

In the third embodiment according to the present invention, as shown inFIG. 5 the light-emitting device 56 and the light-receiving device 57are positioned within the body 51 in planes that hold inclined surfaces52 therebetween and that are symmetric with the sphere 54 positionedbetween the surfaces. On the other hand, as shown in FIG. 10 thelight-emitting device 86 and the light-receiving device 87 may bepositioned on the inclined surfaces 52 so as to be confronted with eachother and in parallel with a horizontal line.

Industrial Applicability

The inclination detecting optical sensor according to the invention isoperationally carried or fixed on an object of interest which is to bechecked for the presence of an inclination greater than a certain angle.If the object and, hence, the sensor is inclined at an angle notexceeding a specified value Θ the inclined surface forms with areference plane or a level plane), the sphere is located at the center,or in the area where the two inclined surfaces meet. If the sensor isinclined to exceed angle Θ, the sphere will move in either direction(clockwise or counterclockwise) toward the end of the inclined surfacedown which the sphere rolls.

If the light-emitting element and the light-receiving element forreceiving the light from the light-emitting element are provided in thecentral part of the body along the inclined surface on opposite sidesthereof, the light issuing from the light-emitting element is blocked bythe sphere and does not reach the light-receiving element if theinclination of the sensor is smaller than the specified angle Θ. On theother hand, if the sensor is inclined to exceed angle Θ, the sphere willmove toward the lowermost end of the inclined surface in the body;hence, the light from the light-emitting element travels unimpeded bythe sphere to reach the light-receiving element, from which it is pickedup as a detection electric signal.

If desired, two pairs of the light-emitting and receiving element, maybe provided near the end portions of the body along the inclined surfaceon opposite sides thereof. In this embodiment, the light issuing fromeach light-emitting element travels unimpeded by the sphere if theinclination of the sensor is smaller than angle Θ and the light ispacked up by the corresponding light-receiving element. On the otherhand, if the sensor is inclined to exceed angle Θ, the sphere will movetoward the end of the inclined surface down which the sphere rolls andthe light issuing from the light-emitting element provided in that endportion is blocked by the sphere and does not reach the correspondinglight-receiving element which, hence, generates no electric signal;however, the light from the other light-emitting element is picked up bythe corresponding light-receiving element, which generates a detectionelectric signal.

Thus, by checking for the generation of an electric signal from thelight-receiving element in response to the inclination of the sensor,one can determine if the object of interest has been inclined to exceeda specified angle (in the first embodiment) or determine the directionin which the inclination has occurred (in the second embodiment). Theinvention enables such detection with a simple apparatus design and in apositive way.

Further, as described in detail on the foregoing pages, the inventionprovides a simple and easy process for producing a sensor that is simplein construction and which yet enables positive detection of theinclination of an object of interest.

The sensor produced by the process of the invention comprises a bodythat has a sphere fitted into a hollow space formed of an inclinedsurface within the body. This contributes simplicity and compactness tothe sensor. What is more, the only moving part of the sensor is thesphere which moves down the inclined surface and, hence, the sensor canbe used with little possibility of the occurrence of operational defectssuch as the moving part sticking in another part. This enables thesensor to detect inclinations with higher reliability.

The foregoing description of the preferred embodiments of the inventionhas been presented for purposes of illustration and description. It isnot intended to be exhaustive or to limit the invention to the preciseform disclosed, and modifications and variations are possible in lightof the above teachings or may be acquired from practice of theinvention. The embodiments were chosen and described in order to explainthe principles of the invention and its practical application to enableone skilled in the art to utilize the invention in various embodimentsand with various modifications as are suited to the particular usecontemplated. It is intended that the scope of the invention be definedby the claims appended hereto, and their equivalents.

What is claimed is:
 1. A process for producing an inclination detectingsensor comprising the steps of:providing a light-emitting device and alight-receiving device; molding an opaque resin to said light-emittingand receiving devices so as to form a body having a hollow space definedby an inclined surface between said two devices; placing a sphere intosaid hollow space; and fitting a lid on said body in such a way as toclose said hollow space; wherein the inclined surface provides a restposition for the sphere when the body having the hollow space is in avertical orientation and permits the sphere to move away from the restposition when the body is inclined by a selected angle from the verticalorientation and wherein the light-emitting device and thelight-receiving device are mounted adjacent to the hollow space at alocation spaced from the rest position of the sphere so thatsubstantially all of a light beam passing from the light-emitting deviceto the light-receiving device is blocked by the sphere to detect thepresence of the sphere when it reaches the selected location butsubstantially none of the light beam passing from the light-emittingdevice to the light-receiving device is blocked by the sphere when it isin the rest position.
 2. A process according to claim 1, wherein saidlight-emitting device and said light-receiving device are each formed byapplying primary molding of a transparent resin to a semiconductor chipmounted to establish electrical connection to leads at an end thereof.3. A process according to claim 1, wherein said molding step isperformed by filling a cavity with the opaque resin, said cavity beingdefined by an upper, a middle, and a lower part of a split mold, witheither one of said light-emitting and receiving devices being positionedbetween said lower and middle parts whereas the other is positionedbetween said upper and middle parts.
 4. A process according to claim 1,wherein said molding step is performed with a split mold having twomiddle parts, one of which has a molding surface with a projecting partthat provides a recess in the body while the other has a molding surfacethat provides outer surfaces for the body.
 5. An inclination detectingoptical sensor comprising:a housing formed with a passage which inclinesupwardly from a rest position within the housing; a body disposed withinthe passage which is normally retained in the rest position when thehousing is disposed in a vertical orientation and which is movable alongthe passage when the housing is titled away from the verticalorientation by an angle greater than a selected angle; and opticalsensor means providing a light beam passing within the passage directlyfrom a light source to a detector at a position where it is notintercepted by the body when the body is in the rest position so thatsubstantially all of the light beam is detected by the detector but isintercepted by the body when the body is at a selected location spacedfrom the rest position.
 6. An inclination detecting optical sensorarrangement according to claim 5 wherein the optical sensor meanscomprises a light-emitting element and a light receiving element whichare disposed on opposite sides of the passage at the selected location.7. An inclination detecting optical sensor arrangement according toclaim 5 wherein the passage is inclined upwardly in opposite directionsaway from the rest position and wherein the optical sensor means includea first optical sensor element providing a light beam at a positionspaced in one direction along the passage from the rest position and asecond optical sensor element providing a light beam extending throughthe passage at a position spaced from the rest position in the oppositedirection along the passage.
 8. An inclination detecting optical sensorarrangement according to claim 5 wherein the passage is inclinedupwardly in opposite directions away from the rest position and theoptical sensor means includes a light-emitting element adjacent to thepassage at a location spaced in one direction from the rest position anda light receiving element at a location adjacent to the passage which isspaced in the opposite direction from the rest position.
 9. Aninclination detecting optical sensor arrangement according to claim 5wherein the body is a member which is rollable in the passage.
 10. Aninclination detecting optical sensor arrangement according to claim 9wherein the body is a sphere.